It is known to provide the glass panes, especially the window panes of automotive vehicles, and particularly safety glass panes which may have a composite or sandwich construction and may consist of two glass sheets joined together, with electrical conductors for a variety of purposes. The conductors may be strips imprinted on one or another of the glass sheets or embedded in the composite structure, wires embedded in the glass or between the glass sheets, or the like.
The conductors can be used for the heating of the window pane, e.g. for deicing, defrosting or removal of moisture. Alternatively, the conductors may form an antenna operating at radio frequencies.
In the past a variety of ways of connecting such conductors to an electrical system of the vehicle or to the radio unit have been employed. For example, a solder element may be provided along the edge of the conductor pattern on the glass pane and can have lugs onto which the lugs of an electrical cable can be plugged. The term "cable" is here used especially to refer to an insulated conductor for the low-current electrical system of a vehicle or for a radio connection or the like.
In one conventional construction utilizing these principles, the solder pad is constituted as a bridge-like sheet metal element which can be composed of a copper alloy or of a similar material and only the feet of the bridge are soldered to the conductor array on the pane. A system of this type is disclosed, for example, in German patent 13 00 039.
Between the feet of the bridge, a bridge span or stirrup is formed which constitutes an elastic or elastically deformable or plastically deformable compensating element capable of yielding with changes in the dimensions of the glass pane and the system to which the glass pane is connected as a result of thermal contraction and expansion.
A connecting lug is formed on the bridge piece and can constitute a plug lug of the type onto which a spade lug can be fitted.
While this construction has been found to be effective to maintain the requisite electrical connection in spite of varying thermal expansion and contraction conditions and deformations which occur at low velocities, when the assembly is subjected to sudden stresses, it is possible for the solder junctions to rupture. This can occur, for example when a cable shoe is applied, when the spade lug is removed or some other maintenance or assembly force is applied.
The stresses which are capable of rupturing the solder junction can also arise during operation as a result of dynamic stresses which are not uncommon in automotive vehicles.